title: Extracellular HSP27 mediates angiogenesis through Toll-like receptor 3.
abstract: The heat-shock protein 27 (HSP27) is up-regulated in tumor cells and released in their microenvironment. Here, we show that extracellular HSP27 has a proangiogenic effect evidenced on chick chorioallantoic membrane. To explore this effect, we test the recombinant human protein (rhHSP27) at physiopathological doses (0.1-10 μg/ml) onto human microvascular endothelial cells (HMECs) grown as monolayers or spheroids. When added onto HMECs, rhHSP27 dose-dependently accelerates cell migration (with a peak at 5 μg/ml) and favors spheroid sprouting within 12-24 h. rhHSP27 increases VEGF gene transcription and promotes secretion of VEGF-activating VEGF receptor type 2. Increased VEGF transcription is related to NF-κB activation in 30 min. All of these effects are initiated by rhHSP27 interaction with Toll-like receptor 3 (TLR3). Such an interaction can be detected by immunoprecipitation but does not seem to be direct, as we failed to detect an interaction between rhHSP27 and monomeric TLR3 by SPR analysis. rhHSP27 is rapidly internalized with a pool of TLR3 to the endosomal compartment (within 15-30 min), which is required for NF-κB activation in a cytosolic Ca(2+)-dependent manner. The HSP27/TLR3 interaction induces NF-κB activation, leading to VEGF-mediated cell migration and angiogenesis. Such a pathway provides alternative targets for antiangiogenic cancer therapy.
authors.affiliation: 1INSERM U866, Faculty of Medecine, 7 Blvd. Jeanne d'Arc, 21000 Dijon Cedex, France. dominique.thuringer@u-bourgogne.fr.
authors.forename: Dominique
authors.initials: D
authors.lastname: Thuringer
authors.forename: Gaetan
authors.initials: G
authors.lastname: Jego
authors.forename: Guillaume
authors.initials: G
authors.lastname: Wettstein
authors.forename: Olivier
authors.initials: O
authors.lastname: Terrier
authors.forename: Laurent
authors.initials: L
authors.lastname: Cronier
authors.forename: Nadhir
authors.initials: N
authors.lastname: Yousfi
authors.forename: Sophie
authors.initials: S
authors.lastname: Hébrard
authors.forename: André
authors.initials: A
authors.lastname: Bouchot
authors.forename: Adonis
authors.initials: A
authors.lastname: Hazoumé
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Joly
authors.forename: Martin
authors.initials: M
authors.lastname: Gleave
authors.forename: Manuel
authors.initials: M
authors.lastname: Rosa-Calatrava
authors.forename: Eric
authors.initials: E
authors.lastname: Solary
authors.forename: Carmen
authors.initials: C
authors.lastname: Garrido
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D055551:HSP27 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000502:physiology*; D051196:Toll-Like Receptor 3 / Q000235:genetics / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism
chemical_list: D055551:HSP27 Heat-Shock Proteins; D016328:NF-kappa B; C495344:TLR3 protein, human; D051196:Toll-Like Receptor 3; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D002118:Calcium
keywords: NF-κB pathway; VEGF release; autocrine VEGFR2 activation; chorioallantoic membrane; endocytosis; microvascular endothelial cell; tubulogenesis